ChainedFastBackendTest.php

<?php

namespace Drupal\KernelTests\Core\Cache;

use Drupal\Core\Cache\ChainedFastBackend;
use Drupal\Core\Cache\DatabaseBackend;
use Drupal\Core\Cache\PhpBackend;

/**
 * Unit test of the fast chained backend using the generic cache unit test base.
 *
 * @group Cache
 */
class ChainedFastBackendTest extends GenericCacheBackendUnitTestBase {
    
    /**
     * Creates a new instance of ChainedFastBackend.
     *
     * @return \Drupal\Core\Cache\ChainedFastBackend
     *   A new ChainedFastBackend object.
     */
    protected function createCacheBackend($bin) {
        $consistent_backend = new DatabaseBackend(\Drupal::service('database'), \Drupal::service('cache_tags.invalidator.checksum'), $bin, 100);
        $fast_backend = new PhpBackend($bin, \Drupal::service('cache_tags.invalidator.checksum'));
        $backend = new ChainedFastBackend($consistent_backend, $fast_backend, $bin);
        // Explicitly register the cache bin as it can not work through the
        // cache bin list in the container.
        \Drupal::service('cache_tags.invalidator')->addInvalidator($backend);
        return $backend;
    }

}